- Tag results for Roger Federer
Federer was barely ruffled as he cruised to a 6-3, 6-2 win over Nick Kyrgios at Chicago's United Center. Zverev saved a match point to defeat John Isner in day two's opening singles rubber.
Team World's Jack Sock and Kevin Anderson needed a tiebreaker to defeat the doubles dream team of Federer and Djokovic 6-7, 6-3, 10-6.
Djokovic clinched his third US Open title on Sunday with a 6-3, 7-6 (7/4), 6-3 triumph over del Potro, taking him level with Pete Sampras's mark of 14 Grand Slams.
Seeded to face Federer in the quarter-finals, Djokovic found himself instead across the net from John Millman after the unheralded Australian stunned the Swiss great.
Djokovic will start the heavy favourite, boasting a 14-4 record over the Argentine who will be playing in just his second final at the Slams.
US Open finalist Juan Martin Del Potro is the next in line to qualify for the 2018 Nitto ATP Finals, which would mark his first appearance at The O2 in London since 2013.
Millman's 3-6, 7-5, 7-6 (9/7), 7-6 (7/3) victory in his first Grand Slam fourth round match scuppered a blockbuster quarter-final between Federer and Novak Djokovic.
Djokovic, winner of US Open titles in 2011 and 2015, extended his dominance over Richard Gasquet with a 6-2, 6-3, 6-3 victory in front of a rowdy night crowd on Ashe.
Millman, 29, downed Mikhail Kukushkin of Kazakhstan 6-4, 4-6, 6-1, 6-3 in the third round of the US Open.
Federer's coolness on the court belied another day where players needed cooling towels as much as their rackets
Second seed and five-time champion Federer made it 18 wins in 18 second round appearances in New York by seeing off error-plagued Frenchman Benoit Paire 7-5, 6-4, 6-4.
Roger Federer sent something of a shock wave through the tennis world with what he thought was an obvious joke after improving to 18-0 in first-round matches at the US Open.
With the temperature topping 33C and the humidity approaching 50% - and that combination making it feel more like 40 C - nearly everything became a struggle for every player across the grounds.
Roger Federer will now face Frenchman Benoit Paire in the second round, with a 6-0 advantage for the former world number one.
Seeded second behind world number one and defending champion Rafael Nadal, Federer could meet the talented if erratic Australian Nick Kyrgios in the third round.